A variety of equipment may be employed in manufacturing microelectronic (e.g., semiconductor) devices. For example, chemical mechanical polishing (CMP) apparatuses are typically used to detect the concentrations of wafer dopants at various stages of processing. CMP apparatuses may also be used to chemically or mechanically planarize the wafer surfaces in an attempt to improve step coverage. In addition, angle polishing apparatuses can be used to chemically or physically cut-process materials. More specifically, these apparatuses typically use bevels to grind the corner sides of the materials.
An example of a conventional angle polishing apparatus is proposed by Mimasu Co. of Japan. In general, this apparatus is typically known as a pre-processing apparatus in that it typically processes wafers prior to the wafers being manufactured into microelectronic devices.
A more precise analysis of processes involved in device manufacturing is generally desirable. Thus, it may be desirable to have a more integrated system in that sample cutting, pre-grinding, angle polishing, wax removal, and wafer surface analysis may be conducted in a coordinated fashion. FIG. 1 is a flow chart illustrating conventional sample processing. First, a predetermined sample size is cut from the wafer. This operation is typically referred to as the cutting step. The cut sample is usually next attached on the angle stage of an angle polishing apparatus by employing conventional electron wax-like resins. This procedure is typically referred to as the attaching step. Electron wax which may be present on the edge of the attached sample is subsequently cleaned (i.e., cleaning step), and the sample surface is then roughly grounded in an attempt to shorten the polishing time (i.e., a pre-grinding step). With respect to the pre-grinding step, the sample is usually attached on the surface of a glass plate, and the thickness of the sample decreases by approximately 2 mm. An example of a commercially employed glass plate is Model No. FO-1200 sold by JAPAN Fujimi Co.
During the grounding operation, the corner of the sample is typically ground while the angle polishing slurry is fed to the surface plate of the apparatus (i.e., an angle polishing step). The sample is next detached from the angle polishing operation, and electron wax which may be present on the sample surface is removed (i.e., wax removal step). Optionally, an etching step such as, for example, a SECCO etching, is carried out prior to performing predetermined analysis steps.
It should be noted that in order to carry out an accurate contaminant (e.g., oxygen precipitate) concentration analysis, it is preferred that the surface of the sample be scratch-free after angle polishing. A conventional slurry typically used for angle polishing comprises between 20 and 21 weight percent of silicon dioxide (SiO.sub.2), between 0.1 and 0.2 weight percent of aluminum oxide, and deionized water. The silicon dioxide particle sizes often range from 10 nm to 20 nm in diameter. An apparatus which may be used to supply polishing slurry is illustrated by FIG. 2. More particularly, the slurry composition is induced from slurry supply tank 1 and is supplied to a surface plate via slurry supply hose 3.
Notwithstanding any possible advantages, potential problems may result when employing silicon dioxide particles having the above sizes. Specifically, when the concentration of silicon dioxide in the slurry is high, the slurry often solidifies in the slurry supply tank 1. When the concentration of silicon dioxide in the slurry is low, there is a heightened possibility that surface scratching may occur during angle polishing. In general, the use of the above silicon dioxide slurries may be disadvantageous in that lengthy times are often needed to polish wafer surfaces such as, for example, 5 hours or greater.
Electron wax removal from a sample is usually carried out by mounting the sample on a gauze or cotton cloth, and then applying an acetone-containing swab to the sample. This procedure, however, is potentially disadvantageous in that the cleaning of the electron wax is often time-consuming. Moreover, the cleaning may involve excessively exposing the sample to the atmosphere. As a result, the sample may become contaminated which often distorts sample analysis.
There is a need in the art for compositions useful for angle polishing wafers to be used in microelectronic devices which reduce the occurrence of wafer scratching. Additionally, there is a need in the art for cleaning compositions which remove electron wax from wafers more efficiently than conventional cleaning compositions in terms of shortened time and reduced contaminant formation subsequent to cleaning.